Movement In And Out Of Cells (Factors Affecting Diffusion (Larger…
Movement In And Out Of Cells
movement of molecules from a region of high concentration to a region of low concentration down a concentration gradient
Digested particles of food diffuse in the colon.
results in a random movement of molecules until an equilibrium is reached
Oxygen diffuses from the blood cells in the blood stream into muscles.
During pregnancy, food molecules and oxygen diffuse from the mother’s blood to the fetus’s blood supply through the placenta.
Oxygen in the lungs diffuses from the alveolar air space into the blood circulating around the lungs.
Factors Affecting Diffusion
Larger concentration gradient causes diffusion rate to increase
Higher temperature causes diffusion rate to increase
Larger surface area causes diffusion rate to increase
Movement of water molecules from a region of high water potential to a region of low water potential through a partially permeable membrane
If conc of solute outside cell > conc inside cell ->
If conc of solute outside cell < conc inside cell ->
If conc of solute outside cell
conc inside cell ->
no change in size
In animal cells:
If there is too much water movement to the cell, it can explode as a result. (
Increasing solution concentration inside the cell causes the cell to become turgid as the vacuole fills up
Decreasing solution concentration inside of cell causes the cell to become flaccid, losing water so the vacuole becomes smaller. The cell body pulls away from the cell wall
Movement of particles through a cell membrane, from a region of lower concentration to high concentration, against a concentration gradient using energy released during respiration
needed when an organism wants to optimise the amounts of ions it can take in
Used in the uptake of glucose in the intestine of the human body
Used by root hair cells of plants for ion uptake